Esterification
By Lydia and Nathan

Introduction
Esterification is the addition of a carboxylic acid molecule and alcohol molecule to form an ester and water.

A Nucleophile is an atom or molecule that gives an electron pair to form a covalent bond

Protonation- the addition of a proton (hydrogen) to a molecule, atom, or ion that changes the charge.

With propanoic acid, there's a carbonyl group and a hydroxide group. In the acid catalyst (a strong acid like H2SO4), a hydrogen gets donated to the methanoic acid. That is called protonation.
This now makes the propanoic acid with a positive charge and an alcohol, 1,2-propanol.

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The alcohol, methanol, gets added to the new alcohol, 1,2-propanol. The carbonyl group is changed to a hydroxide group. Now we have a more complicated molecule with three hydroxide groups, but the reaction isn't done.

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The strong acid (now HSO4) has a negative charge. To become neutral, the molecule will give a hydrogen to the acid to make it neutral.

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Now the molecule consists of two hydroxide groups and an oxygen. A hydrogen from the sulfuric acid will add itself to a hydroxide and will now have a positive charge.

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The last hydroxide group will now make a carbonyl group. The hydrogen in the carbonyl group will go to the acid to make it neutral. With this, an H2O is formed apart from the molecule and an ester is made.

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Esterification does not react with a base. A base catalyst will take a proton from the carboxylic acid, which will make a carboxylate anion. This does not react with a nucleophile.